Cocaine craving has been hypothesized as a potential factor in maintaining drug use or triggering relapse episodes. measurement of craving has been limited to retrospective reports and recall. Retrospective data is subject to error and bias. To overcome past limitations with craving measures, the proposed study is designed to collect descriptive real-time information in the natural environment about immediate events surrounding cocaine craving episodes, using a modified self-monitoring technology. Subjects will be prompted (via electronic pager) to record craving, affect, and situational factors in real-time in their natural environments. Specific analyses will be used to compare: 1) craving intensity across temptation actual drug use, and random situations; 2) identify situational factors that lead to increased craving and use; 3) investigate the association between pretreatrnent variables (e.g., prior use, coping skills, etc.) and cocaine craving intensity; 4)explore differences in craving between users and non-users across the study period. This research should contribute toward an empirical understanding of the relationship between craving and drug use as well as offer a monitoring technology for future treatment research.